Group Assignment of Week-12
This assignment is about documenting what we learned in Molding and casting week that includes understanding different materials used in molding and casting based on their weight ratio, review their safety data sheets and making their test casts.
Objectives of Group Assignment:
1. Review the safety data sheets for each of your molding and casting materials.
2. Then make and compare test casts with each of them.
Materials that we have tested:
1. Ecoflex rubber- platinum catalysed silicones
2. RTV2 Silicone rubber - 15C white
3. Forticast ERS LV
We tested all the above materials by each one of us and went through their safety data sheets which consists of it's density, mixing ratiio, cure time, etc. We used all different molding and casting materials available at our Sanjivani Fab Lab. We made their test casts and observed proportion, mixing methods and curing time for each one of the materials. We also learned which material can be used as a molding material and whichh one as casting material. Some of them can be used as both molding and casting materials.
Materials Used
Ecoflex rubber - platinum catalysed silicones
Ecoflex rubbers are platinum catalysed silicones that are versatile and easy to use. Ecoflex rubbers are mixed in the ratio of 1A:1B by weight or volume and cured at room temperature with negligible shrinkage. Ecoflex rubbers are versatile materials, perfect for a wide range of applications, from crafting prosthetic limbs to creating realistic special effects in movies. Mixing them is straightforward—just combine equal amounts of two components, and you're ready to pour. Once cured, the resulting rubber is remarkably soft, yet incredibly strong and stretchy, making it ideal for various uses. You can even add pigments to create custom colors for your projects. However, it's crucial to work safely, ensuring proper ventilation and wearing protective gear like gloves and glasses. After pouring the mixture onto your chosen surface, allow it to cure at room temperature before demolding. For the best results, clean your mold thoroughly before storing it in a cool, dry place. With these simple steps, you can unleash your creativity and bring your ideas to life with Ecoflex rubbers.
Features
1. Versatility : Suitable for diverse applications including prosthetic appliances, orthotic cushioning, and special effects like animatronics.
2. Ease of Use : Mixed in a 1A:1B ratio by weight or volume, with low viscosity for easy mixing and de-airing.
3. Strength and Stretchiness : Cured rubber is soft, strong, and highly stretchable, rebounding to its original form without distortion.
4. Transluencency and Pigmentation : Water white translucent nature allows for color pigmentation with Silc Pig pigments, enabling a variety of color effects.
5. Thickening and Thinning : THI-VEX silicone thickener can be added for brushable applications, while Silicone Thinner reduces viscosity for easier pouring and vacuum degassing.
Instructions
Safety : Use in a properly ventilated area, wearing safety gear like glasses, long sleeves, and vinyl gloves.
Cure Inhibition : Certain contaminants may inhibit curing, so test compatibility with the surface.
Release Agent : Although usually not necessary, a release agent like Ease Release 200 facilitates demolding.
Measuring and Mixing : Mix Parts A and B thoroughly for 3 minutes, then vacuum degas to eliminate entrapped air.
Pouring and Curing : Pour mixture uniformly, ensuring at least 1/2” coverage over the highest point of the model. Cure at room temperature before demolding, with optional post-curing for maximum properties.
Mold Performance and Storage : Mold life depends on usage and materials cast. Clean and dry molds before storage in a cool, dry environment.
RTV2 Silicone rubber - 15C whitev
15C White is a poly-condensation curing, two-component silicone that vulcanizes at room temperature. It has low shore A hardness, high tear strength and low dimensionnal variation. It is generally used foor applications like general mouldmaking and construction mouldmaking.
Before the casting of Epoxy, Polyester and PU resins on the silicone please apply a release
agent to protect the silicone mould. If the resin is aggressive, apply it for each
casting.
If you are using this silicone with a particular resin for the first-time, please do a small test
so it does not compromise the work.
Take the two bi-component products and shake before use in order to homogenize each
component prior to mixing. BASE component is white, CATALYST component is transparent/
yellowish.
Mixing ratio must be 100:5 (5 units of CATALYST for every 100 units of BASE). For example,
for 1 kg of base, add 50 g of catalyst. This ratio must be respected to ensure the final char-
acteristics of the product. DO NOT exceed the recommended ratio for the catalyst. You can
use less catalyst (3-4%) than the recommended ratio (5%), in this case the dimensional
change will be lower but setting time will increase. The hardness is reached after a few hours (see table) and if the correct percentage of
catalyst is respected. After 24 hours the product is cured. After 72 hours,
perfectly hardened.
Mix vigorously until the mixed white color is homogeneous. Once the product is completely
mixed, it is ready to be poured and it is recommended to pour the silicone from a height of
30 cm into the mold.
Complete curing takes about 72 hours after mixing the two components.
Features:-
1. Two-Component System:- Connsists of a base (Part A) and a curing agent (Part B).
2. Room Temperature Vulcanization(RTV):- Cures at room temperature without the need for heat.
3.High Tear Resistance:- Provides durable molds that can withstand multiple castings.
4. Flexibility:- Offers excellent flexibility, allowing for easy demolding of complex shapes.
5. Low Shrinkage:- Ensures dimensional stability of the molds and castings.
6. Excellent Detail Reproduction:- Captures fine details from the master model.
7. Chemical Resistance:- Resistant to various chemicals, making it suitable for diverse casting material.
8. White Color:- 15C White provides good visibility of details and a clean appearance.
Safety Precautions:-
Personal Protective Equipment:- Wear gloves, safety gogglees and protective clothing when handling silicone rubber components.
Ventilation:- Use in a well-ventilatedd area to avoid inhalation of fumes.
Storage:- Store components in tightly sealed containers in a cool, dry place. Avoid exposure to moisture and contaminants.
Forticast ERS LV
Forticast ERS LV is a clear castable epoxy system. This product can be used to make small functional
parts (due to its high strength) where optical clarity is important.
Forticast ERS LV is mainly used for creating decorative items through casting due to its brilliant optical
clarity and as a mould making material for Printing Pads.
The low viscosity allows this product to seep into small details for encapsulations. This product can also
be used without a vacuum chamber without bubble trapping to some extent. Mixing ratio is 2:1
Features:-
1. Low Viscosity:- Easy to mix and pour, ensuring thorough coverage and penetration into molds or substrates.
2. High Clarity:- Provides a clear finish, ideal for aesthetic applications.
3. Good Mechanical Properties:- Offers strength and durability in the finished product.
4. Excellent Adhesion:- Bonds well to a variety of substrates, including metals, plastics, and composites.
5. Chemical Resistance:- Resistant to many chemicals, making it suitable for industrial applications.
.
6. Electrical Insulation:- Provides good insulating properties, suitable for electrical and electronic encapsulation.
7. Thermal Stability:- Can withstand moderate heat exposure without degrading.
Safety Precautions:-
Personal Protective Equipment:- Wear gloves, safety gogglees and protective clothing when handling silicone rubber components.
Ventilation:- Use in a well-ventilatedd area to avoid inhalation of fumes.
Storage:- Store components in tightly sealed containers in a cool, dry place. Keep away from direct sunlight and sources of heat.